login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A059729
Carryless squares n X n base 10.
27
0, 1, 4, 9, 6, 5, 6, 9, 4, 1, 100, 121, 144, 169, 186, 105, 126, 149, 164, 181, 400, 441, 484, 429, 466, 405, 446, 489, 424, 461, 900, 961, 924, 989, 946, 905, 966, 929, 984, 941, 600, 681, 664, 649, 626, 605, 686, 669, 644, 621, 500, 501, 504, 509, 506, 505
OFFSET
0,3
EXAMPLE
a(87) is carryless sum of (6)400, (5)60, (5)60 and (4)9, i.e., 400+20+9 = 429.
PROG
(Python)
def A059729(n):
s = [int(d) for d in str(n)]
l = len(s)
t = [0]*(2*l-1)
for i in range(l):
for j in range(l):
t[i+j] = (t[i+j] + s[i]*s[j]) % 10
return int("".join(str(d) for d in t)) # Chai Wah Wu, Jun 29 2020
(PARI) a(n) = fromdigits(Vec(Pol(digits(n))^2)%10) \\ Ruud H.G. van Tol, Dec 07 2022
CROSSREFS
See A087019 (lunar squares) for another version.
Sequence in context: A008959 A316347 A169917 * A184988 A108533 A200414
KEYWORD
base,easy,nonn,look
AUTHOR
Henry Bottomley, Feb 20 2001
STATUS
approved